I have a table that has data which looks like this:
L1 1 0 u1
L1 1 0 u2
L2 1 0 u1
L2 1 0 u2
L2 1 0 u3
and I would like the result to look like this:
L1 1 0 u1_u2
L2 1 0 u1_u2_u3
For each value in the first 3 rows, all the values in the 4th column need to be listed as comma or underscore separated values(concatenated).
I have tried using XMLAGG function but its very slow and has high CPU usage. Is there any better way to do it in Teradata SQL? Thanks in advance!!